Method for cleaning paint spray guns and the like



' March 19, 1957 J. E. ROACH 2,786,000

METHOD FCR CLEANING PAINT SPRAY GUNS AND LIKE Original Filed Sept. 1,1950 '11 s @rm nil ow 1 1 r;l" h

INVENTQR James E. Roach ORNEY United States Patent METHOD FOR CLEANINGPAINT SPRAY GUNS AND THE LIKE James E. Roach, Battle Creek, Mich.,assignor to Evron L. Kline, Battle Creek, Mich.

Original application September 1, 1950, Serial No. 182,729, now PatentNo. 2,682,273, dated June 29, 1954. Divided and this applicationFebruary 18, 1954, Serial No. 411,087

3 Claims. (Cl. 134-21) The present invention relates broadly to methodsof. cleaning equipment, and in its specific phases to a method ofcleaning paint spray guns.

Spray painting has become a big industry and is used for the painting ofitems varying in size from small articles to buildings. Each time that ajob is finished, a days work is over, or the color or kind of paintbeing sprayed is to be changed, the paint spray gun must be thoroughlycleaned both inside and out or else it will not be in proper conditionfor reuse. The standard procedure for doing this cleaning of paint sprayguns has been to immerse same in a suitable solvent such as thinner,turpentine, gasoline, naptha, benzol, or the like. After the paint orthe like on or in the gun has been soaked loose, it is common practiceto rinse it off with a solvent and then throw the solvent away. Thesolvent thus discarded makes this procedure costly and moreover thecleaning of the spray gun in this manner is not as good a is normallydesirable. It was a recognition of these shortcomings in the spraypainting art and the complete lack of a thoroughly satisfactoryapparatus for economically and thoroughly cleaning paint spray guns,which led to the conception and development of the present invention.

Accordingly among the objects of the present invention is the provisionof a new method suitable for the efiicient and economical cleaning ofpaint spray guns.

Another object is to provide a new method for cleaning paint spray gunswherein the same solvent may be used several times before it isnecessary to discard same.

Another object is to provide a paint spray gun cleaning method whichpermits simultaneously cleaning both the inside and outside of the gun.

Another object is to provide a method of cleaning paint spray guns, andthe like, wherein a suitable solvent is sprayed under pressure onto thegun being cleaned so as to not only dissolve the accumulated materialthereon,

but forcibly flush it away.

A further object of the present invention is to provide an improved andhighly simplified method of cleaning paint spray guns and the likewherein a suitable solvent is forced through the gun and out its nozzle,and simultaneously a suitable solvent is sprayed over the gun underpressure to clean the outer surface of same.

Still further objects and advantages of the present invention willappear as the description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, consists of the method steps hereinafter fully described andparticularly pointed out in the claims, the annexed drawing, and thefollowing description setting forth in detail certain modes of carryingout the invention, such disclosed modes illustrating, however, but oneof the various ways in which the principles of the invention may beused.

In the annexed drawing:

Figure 1 shows a partially sectioned front elevational view of apreferred form of the present cleaning apparatus with the front removed.

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Figure 2 shows a top view of the apparatus of Figure l with the toppanel removed.

Figure 3 shows a partially sectioned side elevational view was takenfrom the right side of Figure 1 with the side and can cleaner removed.

Figure 4 shows an enlarged center sectional view through a preferredform of one of thenozzles used in the present cleaning apparatus.

Referring more particularly to the drawing, it will be noted that thepresent cleaning apparatus 1 has a housing 2 with a liquid tight bottompanel 3, and a fluid tight top panel 4. Vent connection 5 may extendupward from top panel 4, or any other convenient location in the upperportion of housing 2, and the showing is intended to be considered asdiagrammatic of the various positions it may take within the scope ofthis invention. The front of the housing is provided with a door 6 whichis mounted on hinges 7 and provided with a latch 8. In preferredconstruction this door would be provided with a conventional gasket (notshown) of synthetic rubber to prevent leakage during operation of theapparatus. Bottom panel 3 of the housing will also be provided with apetcock 9 for use in withdrawing solvent from the apparatus wheneverdesired. The back panel of the housing 2 is preferably provided withupturned vapor vents 10 for a purpose to be hereinafter explained. Thewhole assembly, when not used as a bench model, is provided withsuitable length supporting legs 11.

Pipe 12, connected to a suitable source of air under pressure, (notshown), has connected to it valves 13, 14, and 15 by means of fittings16, 17, and 18. Valve 13 is connected to a pipe 19 which extends throughthe front of housing 2 and thence substantially to the top of same whereit forms a return bend member 20 which is provided with a multiplicityof perforations 21 in its under face for use in blowing solvent off ofthe paint spray gun 22, shown by dotted lines in Figure 3, after samehas been cleaned and is ready to be removed from the housing.

Valve 14 is connected to pipe 23, Figure 3, to which is connected aT-member 24 on which is mounted an air chuck 25 adapted to receive andhold paint spray gun 22. Nipple 26 connects T-member 24 to a secondT-member 27 which is conventionally joined to both ends of a return bendtube 28 on which are mounted several spray nozzle assemblies 29 by meansof tubes 30.

The spray. nozzle assemblies 29, Figure 4, utilizes a tubular bodymember 31 open at its lower end for a purpose to be hereinafter setforth and provided with a nozzle 32 at its upper end. Tube 30, .which isof smaller size than tubular body member 31, preferably extends throughthe side of same and has its open end directed toward nozzle 32. Thesenozzle assemblies can be directed at the outer surface of the spray gunfrom various angles and one of the nozzles is preferably aimed at asplash plate member 33 mounted on the back wall of housing 2, which willdirect sprayed cleaning fluid over the nozzle end of the spray gun andpaint can cover member 42 of same. A ring member 34, Figure 3, may beused to hold the trigger 40 of the paint spray gun 22 in sprayingposition, as shown, for a purpose to be hereinafter described.

Mounted on the bottom of a spray gun, when in use, is a can 35, shown bydotted lines in Figures 1 and 2, and in which is placed the paint orother liquid to be sprayed. This can 35 also needs cleaning along withthe spray gun and accordingly a clamp 36 is mounted, as by means ofscrew 37, inside of housing 2 so as to hold the paint can 35 with itsopen end down. In this position the spraying of cleaning liquid, bymeans of spray nozzle assemblies 29, will clean and flush the outer faceof can 35. The inside of the can is cleaned by means of a spray nozzle29a connected by means of a pipe 38 to valve 15;" The upper end of spraynozzle 2% is preferably provided with a spreader member 39 which causesthe sprayjo be.flared outward and to whirl in orderto give more rapidcleaning action. V

In use, the .cleaningapparatus 1 has its vent connection5'connect'edfor-exhaust throughla suitable Pip [0 the outdooratmosphere, while pipe 12 is connected to. a suitable source of .airpressure which, forinstance, may be at a gage pressure of 35 pounds persquare inch, although this pressure can vary over a wide range andstill, be completely satisfactory. The bottom of housing 2 being, liquidtight can be filled with a suitable cleaning liquid .to alevel below thetops of spray nozzle assemblies 29*and 29a. For most purposes, about aninch or two of cleaning'liquid in the bottom of housing 2 will meetordinary. requirements and" same will reach approximately halfiwaydo"the top of spraynozzle assemblies 29*and 2911, At "thesame'time, thislevel should not be higher'thanithe'bottont of vapor vents which relievethe'suction .pressure created within housing 2 under operation ofthe'spray nozzles.

The'open lower-end oftubular body member 31 of the spraynozzles 29 and29a is closely adjacent but spaced frombottompanel 3"of'housing 2'sothat when the air valves 14 and 15 'areopened the air flowing throughtubes -will cause EVSllCllOIY'fifieCt which will draw the solvent liquidup through tubular body member 31 and cause it to besprayed with the airout of nozzle 32.

To use thepresent-spray gun cleaning apparatus, the paint spraygun can35 is first mounted in the position shown in dotted *lines-in' Figures 1and 2. Removable clip 34 is then mounted on the paint spray gun 22 toholdthe trigger 40in retracted or spraying position. The gun 22 is thenmounted on the air chuck 25 in the positionsh'own' in dotted lines inFigure 3 with the paint flow tube 4l exte'nding substantially to thebottom of housing 2;- The opening ofvalve 14 will then force airthrough-paint spray gun 22 'and in doing so will draw cleaning 'flui'dupthrough. paint flow tube 41 of the "gun andflush out the'insi'de ofsame. At the same time, air Will -flow 'through' the spray nozzleassemblies 29'and spray cleaning liquid over the outside of the spraygun to dissolveiandnflush away the paint which has accumulatedi'thereon:This spraying of course will also clean andi-flushxpaint fromuthe'outersurface of can 35.

The openingofvalve 15 in turn will cause spray nozzle29a.to'spraycleaning.fiuidinto theinside .of the can tocleanand-fiuslisam'e; Both .valves.14 and 15 can beoperatedsimultaneously ifldesired, and under actual practice the:cleaningeof arspray gun andcan, in most cases, can be accomplishedlverythoroughly in'less than a minute. Valves l4'and l5 will then be closedand valve 13 opened to blowair:through return bend pipe 20 andperforations'21,,onto -the paint spray gun 22 to quickly 4- dry sameready for removal through door 6. After the cleaning fiuidlias becomesuflicintly contaminated with paint and the like, it can be withdrawnthrough petcock 9 and discarded, following whicha fresh supply ofcleaning fluid can be placed in. housing 2 so as to be ready for useonce more.

The present-invention is a: division of my, copending patent applicationSerial No. 182,729, filed September 1, 1950, which was granted June 29,1954, as Patent No. 2,682,273;

Other modes of applying the principle of'my invention may be employed:instead of the oneexplained, change being. made. as regards the stepsherein disclosed, providedthose stated by any of the 'followingclaim's-or their equivalent be employed.

1 therefore particularly point out and distinctly claim as my invention:

1. The method of cleaning a paint spray gun with the paint supply tube'of the gun extending'into a body of solvent liquid,which"":c0mprises'the steps'of' passing air under pressure through saidgun to draw said'solvent liquid through said gunto clean the interiorthereof, and separately. spraying a portion of said liquid solvent oversaidguntoclean th'e'outer surface'of'sam'e.

2.' The meth'od'of cleaninga paint spray gun with the paint supply tube'of said gun 'extendinginto a body of solvent liquid, which'consists'ofthe steps of passing air under pressure through said' gun todraw said solvent liquid-through said gun to clean the interior thereof,and simultaneously separately withdrawing some of said liquid solventfrom said body thereof and spraying it under air pressure over said gunto clean the outer surface thereof.

3. The method of. cleaning a paint spray gun with the paintsupply tubeof said gun extending'into a body of liquid solvent, which consists of'the steps of passing air under pressure through said gun to draw saidliquid solventthrough said gun to clean the interior thereof,simultaneously separately withdrawing some-of said liquid solvent fromsaid'body thereof and spraying it under air pressure over saidgun toclean the outer surface thereof, and drying the outer surface of saidgun by blowing air overit under pressure'after stoppingthe flow of saidliquid'solvent through and over said gun and before removing the latter.

References Citedin'the file of this patent UNITED STATES PATENTS 620,224-Bubser Feb. 28, 1899 831,084 Lisa Sept. 18, 1906 1,438,834 Keil Dec.12, 1922 2,309,251 Little Jan..26, 1943 2,536,208 Nystrom Jan. 2, 19512,598,963 Armstrong June 3, 1952

1. THE METHOD OF CLEANING A PAINT SPRAY GUN WITH THE PAINT SUPPLY TUBEOF THE GUN EXTENDING INTO A BODY OF SOLVENT LIQUID, WHICH COMPRISES THESTEPS OF PASSING AIR UNDER PRESSURE THROUGH SAID GUN TO DRAW SAIDSOLVENT LIQUID THROUGH SAID GUN TO CLEAN THE INTERIOR THEREOF, ANDSEPARATELY SPRAYING A PROTION OF SAID LIQUID SOLVENT OVER SAID GUN TOCLEAN THE OUTER SURFACE OF SAME.